Angelina Jolie and Brad Pitt throw Knox and Vivienne fun 7th birthday party

It may besummer but Angelina Jolie and Brad Pitt's twins enjoyed some winter fun ontheir 7th birthday. Knox and Vivienne Jolie-Pitt celebrated their big daywith their famous parents on Sunday at an ice rink.

The famousfamily, including Knox and Vivienne's older siblings, Maddox, 13, Pax, 11,Zahara, 10, and 9-year-old Shiloh, were spotted leaving Iceland Ice SkatingCenter in a suburb of Los Angeles on Sunday, all with big smiles on theirfaces.

"Theyrented a bus and headed for an afternoon of ice-skating," an eye witnesstold Us Weekly, adding that some of the twins' friends joined in on the fun."Knox and Viv were bundled up with snow hats and mittens. They were reallyexcited about it."

Photo: Getty Images

The onlooker added: "Everyoneskated for about two hours and they tried out special bumper cars on theice. They were spinning around getting dizzyand had a blast. Some of the kids were holding hands as they skated and it wasreally sweet."

Thechildren were "wiped out" as they got back on the bus to go home. Despite her young age, Vivienne has already had one big role on the big screen. InAngelina’s 2014 film Maleficent, she played the young PrincessAurora, while her siblings Zahara and Pax had smaller walk-on parts.

"Ithad to be Viv," Angelina later explained to Entertainment Weekly."The other three and four-year-old (actors) wouldn't come near me. It hadto be a child that liked me and wasn't afraid of my horns and my eyes and myclaws… When Pax saw me for the first time, he ran away and got upset."

Brad with his parents and their three oldest at Unbroken premiere Photo: Getty Images

Despite Viv’sstrong acting genes, the actress was pleasantly surprised at how well herlittle one took to the role. Mother anddaughter do have an especially close bond; Vivienne also likes to followAngelina around. "She'salways that kid, she's that little girl," Angelina told E! News last year. "We call her my shadow at home… The other kids are starting toget a little irritated about it!"